Some surprise while "dd-ing" a video DVD...
a.giuliano at iccu.sbn.it
Wed Jan 18 13:50:42 UTC 2006
I'm doing some practice with video DVDs, and after some experiments I'm
now able to make divx with dvd::rip, or even with transcode without
serious problems. I post this just because I was curious about the ways
to dump video DVDs on hard disk at a lower level, and I ran across some
strange behaviour I cannot explain by myself.
I know that a video DVD has an ISO9660 filesystem, just like any data
DVD or CD (if I'm not wrong). So I thought I could create an ISO image
of a video DVD using "dd" or "readcd", for instance.
But "dd" issues an "input/output error" after a few seconds, and so does
"readcd". I thought this could be due to the encryption used on video
DVDs, but Nautilus can mount video DVD without problems, how can it do that?
Then, the solution came by itself: I just viewed a few seconds of the
DVD with "mplayer", then tried again with "dd" and... voilà, "dd" goes
on and on till all the ISO image is copied on my hard drive (a few hours
later...). I did all the above absolutely without any intention, I just
noticed that it worked!
What did "mplayer" do that allowed "dd" to work?
You have to know that:
1) all this happens with several different video DVDs;
2) the DVD drive is rather new (August 2005);
3) the disks work perfectly on my DVD player (I mean, they are original,
not copies, they are clean, they have no scratches, and so on)
4) I run Breezy, updated.
Andrea Giuliano, Ph. D.
ICCU - Istituto Centrale per il Catalogo Unico
Viale Castro Pretorio 105, Rome - ITALY
Tel. +39 06 49210403, Fax +39 06 4959302
More information about the ubuntu-users